This is a Trimble Navigation System stand alone GPS from 1990's. Contains the power cord with 9 volt battery wired for backup, external antenna and the unit itself. It sends data out the port to a computer is a serial stream. System comes with Null Modem adapter, M-M Gender Bender, 9 pin to 25 pin DB connector for hooking up to a variety of serial port configurations. Output data 1 line per second. https://www.youtube.com/watch?v=mCFnvWnTaCM